Immersion heater for liquids



March 13, 1951 J. c. WIESNER ETAL IMMERsIoN HEATER FOR LIQUIDS 2 Sheets-Sheet l Filed Jan. 14, 1949 Jerry C. Wiesner James l?. Carey INVENTORA` BY #Wwf/mm March 13, 1951 J.c.w1EsNER ETAL 2,545,418

IMMERSION HEATER FOR LIQUIDS Filed Jan. 14, 1949 2 Sheets-Sheet 2 Jerry 0. Wiesner j ln James Carey INVENTORl BY 5mm Patented Mar. 13, 1951 IMIVIERSION `HEATERfFOR LIQUIDJS.

Jerry C.Y Wiesner, Granville, andJames R..Carey, Albany, N Y.'

Application January 14, 1949, Serial No; 70,932

5 Claims. 1

This` invention relates to new` and useful improvements and structural refinements inV im-V mersion-type heaters for liquidseither, liquid in closed containers such as hot Watertanks, pres, sure cookers, cooling jacketsor internalcombustion engines, etc.,.or in open containers `.such as double boilers, percolators, etc., and. in particu, lar'theinvention concerns itself With that type of an immersioncheater wherein two... or more electrodes areimmersed in and are in .electrical contactwith theliquid to be heated, so thatthe liquid'itself actually becomes a part of the` electricalcircuit and by offering aresistance thereto, the desired heating effect is'created.

Some of the objects of this inventionare to eliminate the breakage of electrodes, to substantially minimize electrolytic activity ,such as would produce undesirable coating or deposit/of, foreign matter on the electrodes, to substantiallyrninimizeif not completely eliminate disintegrationof 20 the electrodes by eleetrolytic action, and to assure proper circulation of the liquid around the electrodes so as to substantially increase the operating efficiency of the heater ascompared to heaters or conventional type.

Additional objects of the invention areA to eliminate arcing between the electrodes, to pre-- vent undesired discoloration oi theiliquidbeing heated, to prevent any taste from being imparted to the liquid by the heating action, and to render the heater fully automatic in operation ands capable of maintaining the liquid at a predetermined degree of temperature.

These objects are achieved bythe provision of the instant heater, wherein the electrodes vare firmly and securely supported inspaoed relation so as to eliminate thel possibility of breakage while assuring proper circulation of the Vliquid' therebetween, wherein the electrodes are constructed from a particulartype oimaterial which is'non-corrosivef and adapted' to discourage or' repel accumulation of' foreign matter thereon,A and wherein adjustable, thermostatica'lly actu-- atedmeans are provided for controllingf'the "ilow of. current through theelectrodes so'as tovmaintain' the liquid at a predetermined degreeaofteml perature.'`

Some of the advantages of the inventionlierin itsisimplicity of construction, ingitsradaptability tozexpeditious' disassembly for purposes` of;` in-v spection orv repair, and inits; adaptability to economical manufacture.

With the abovelmore important objects and features .in View, and such other. objects and features as may become apparentasthisspecifica- 55l tionproceeds, the invention consists essentially of the arrangement and construction of parts as illustrated in the accompanying drawings, in which:

Figure 1 is a side-elevational View of the invention;

Figure' 2 is a longitudinal cross-sectional View.`

thereof, taken substantially in the plane of the line 2-2in Figure l;

Figure 3is an end View, taken in a directionof the arrow 3 in Figure 2;

Figure fi is a cross-sectional view, taken substantially'in the piane of the line fl-l in Figure l Figure 5 is a cross-sectional View taken substantially in the plane of 'the line 5-5 in Figure 2;

Figure 6 is a cross-sectional View, taken substantially in theplane of the line 6'-6 in Figure 2; and

Figure 7 is a fragmentary perspective view'of a-control rod used in the invention.

Like characters of reference are employed to designate like parts in the specification and throughout the several views.

Referring nowto theY accompanying drawingsv ,i l2 including a polygonal wrench-receiving portion lf3; one end surface of the head l2 being formed with aacircular recess i t to receive a diskshaped electrode holder ES formed from suitable insulating material.

A iurtner'electrode holder 2i! of similar construction is disposed in spaced, axially aligned position relative to the holder IE, and a tubular stem 22 extends axially through the holders I8, 20, as is besty shown in Figure 2.

A cylindrical housing 24 is associated with the holder 2D 'by having this holderpositioned'adjacent one end thereof as shown inFigure 2,Y the housing beingjformed with ascreW-threaded:

boss 2S to receive a screw-threaded end portion oi the stem 22,V as will be clearly apparent.

a,- cylindrical loorell with` Whichthe headisproe vided. This end portion of the stem 22 isalso. screw-threadedto receive a securing nut. 32,and suitable packing 34 may, of courser beusedfor preventing leakage ofV liquidinto .the bore 30;- of

3 the head, as will be clearly apparent (see Figure 2).

A set of electrodes Sli-e, inclusively, are securely mounted between the holders i8, 29, this being achieved by providing the holders with suitable recesses as exemplified at 52, to receive end portions of the electrodes. It will be observed that by tightening the nut 32, the holder 2i! t0- gether with the housing 24 will be drawn toward the head i2 and, as a result, the electrodes will be firmly secured in position between the holders thereof. The electrodes 3-5 preferably assume the form of flat straps disposed in juxtaposed relation and arranged in a substantially cylindrical formation so that a longitudinal edge of one strap is laterally staggered from the corresponding edge of the next adjacent strap, as is best shown in Figure 4. When the invention is installed, the head l2 should be so adjusted that the electrode straps are disposed in vertical planes, thus assuring proper circulation of liquid therebetween by forces of convection.

The electrode straps are preferably formed from silver plated copper alloy or beryllium copper of the following composition:

Per cent Beryllium 2.5 to 3.0 Nickel 0.6 to 0.8 Iron 1.2 to 1.3 Copper 94.9 to 95.7

A switch assembly 54 is provided in the bore 9@ of the head i2, this switch assembly embodying a hollow, substantially cylindrical housing 5t which is positioned in the bore Si) and is formed with an annular groove 53 to accommodate a set screw 69 with which the head l2 is provided, whereby the switch assembly is retained in position in the head.

l An adapter 62 is secured to the switch housing 5S by a plurality of screws G4 and is disposed exteriorly of the head l2, being formed with a pair of sockets 66, 58 toreceive the usual prongs of a conventional attachment plug (not shown) whereby a supply of electric current is delivered to the heater.

One of these sockets, namely, the socket 63, is connected by suitable conductors 'Eil extending in the head i2 to the electrodes 35, Alli, 44, 45 and 48, while the remaining electrodes 38, 42, 43, d and 59 are similarly connected by additional conductors l2 to a stationary contact member 74 provided in the housing 56 of the switch 54. A swingable contact arm l@ is pivotally mounted in the switch housing as at 'i8 and is separably engageable with the contact member '54, the arm l5 being, in turn, electrically connected to the remaining socket 96 by a conductor 89.

A suitable tension spring 82 is anchored at one end to the adapter 62 as at 84 while the remaining end of the spring is anchored to the arm 16, whereby the arm is normally maintained out of contact withthe member 14, thus normally maintaining the switch assembly 54 inits open position.

A longitudinally shiftable switch control rod 8E is slidably disposed in the aforementioned stem 22, one end portion of this rod extending into the aforementioned housing 24 and being suitably secured to a helical, expansible thermostat 88, the free end of which, in turn, is secured to the housing 24. The thermostat 33 is of the conventional bymetallic construction, as indicated in Figure 2.

The rod 86 extends into the switch housing 56 and is cross sectionally reduced as indicated at so as to provide sufcient clearance for an intermediate portion of the aforementioned switch arm '56. The end portion of the rod 86 disposed in the switch assembly 54 terminates in a split tubular extremity 92 which is screw-threaded to receive an adjusting screw 94, the shank of this screw being engageable with the arm 1B while the head portion of the screw is disposed in a counterbore 96 provided in the adapter 62, Whereby the screw is externally accessible for purposes of adjustment.

Having thus described the construction of the invention, its method of operation will now be explained.

Primarily, it is to be observed that the conductors i9, 12 of opposite polarities are connected alternately to the electrodes Sii-59, that is to say, regardless of whether direct or alternating current is used, the polarity of one electrode is always different from that of the next adiacent electrode, so that a diierence of potential is established between the immediately adjacent electrodes in the set. It should, of course, be understood that when the heater is installed, the several electrodes are in electrical contact with the liquid to be heated so that the liquid actually becomes a part of the electrical circuit resulting from the diierence of potential between the next adjacent electrodes and the liduid offers sufficient resistance to the passage of electricity therethrough to create the desired heating effect.

The dierence of potential between the electrodes is present when the switch arm 1'6 is in engagement with the switch member 74, and when the temperature of the liquid ultimately reaches a predetermined point, the thermostat 88 will slide the rod 85 in the direction of the arrow (see Figure 2) so that the arm 'Iii will become separated from the switch member 'I4 by the resiliency of the tension spring 82 which tends to draw the arm 'i6 against the shank end of the adjusting screw 94. Needless to say, by simply rotating the screw 94 in one direction or the other, the temperature at which the switch assembly 54 is opened may be varied, as desired. In any event, opening of the switch 54 will interrupt the supply.

by crimping, or the like, so that the screW- 4 threaded bore |90 of this rod portion is not of a Y true cylindrical form, whereby the coeflicient of friction of the screw 94 in the bore |09 will be substantially increased and undesired rotation of i the screw, such as would disturb its predetermined adjustment, will be prevented.

It is believed that the advantages and use of the invention will be clearly apparent from the foregoing disclosure and, accordingly, further dcscription thereof at this point is deemed unnecessary.

While in the foregoing there has been shown and described the preferred embodiment of this invention it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

Having described the invention, what is claimed as new is:

1. In an immersion type liquid heater, the combination of a mounting head, a set of flat electrode straps disposed in juxtaposed relation and secured at one end thereof to said head, an insulating holder provided on the remaining end portions of said straps, a tubular stem disposed between said straps and securing said holder to said head, said straps being adapted for immersion in and electrical Contact with the liquid to be heated, and current conductors of opposite polarities extending into said head and each connected to alternate straps of said set whereby a difference of potential may be established between the immediately adjacent straps of said set, a switch connected to one of said conductors for breaking the circuit and positioned in said head, a housing secured to said stem having a coiled bimetal thermostat therein, a rod in said stem xed to one end of said thermostat and adapted to open said switch at a predetermined temperature.

2. The device as dened in claim 1, wherein said straps are of different widths and are mounted in a substantially cylindrical formation whereby a longitudinal edge of one strap is laterally staggered from the corresponding edge of the next adjacent strap.

3. In an immersion type liquid heater, the combination of a mounting head, a set of elongated electrodes disposed in juxtaposed relation and secured at one end thereof to said head, a housing provided at the remaining ends of said electrodes, a tubular stem positioned between said electrodes and securing said housing to said head, a switch mounted in said head, conductors extending into said head and connected to said electrodes through the medium of said switch, an expansible coil thermostat in said housing, and a longitudinally shiftable control rod positioned in said stem and operatively connecting said thermostat to said switch.

4. The device as dened in claim 3, together with an externally adjustable screw provided on said rod in said head, said switch including a pivoted contact arm, and said screw being operatively engageable with said arm, and resilient means for normally urging said switch to open position.

5. A liquid heater comprising: a mounting head having an insulating holder mounted therein, a tubular stem secured to said mounting head at one end and having a housing xed to its other end, a plurality of electrode straps positioned with their upper ends in said insulating holder and their lower ends in a second insulating holder mounted on said housing, conductors of opposite polarities extending into said head, each of said conductors connected to a plurality of alternate straps for providing a difference of potential between the straps, a switch interposed in one of said conductors, an extensible thermostatic coil in said housing having a rod attached to one end thereof, said rod being concentric with said tubular stem and having its upper end cooperable with said switch and adapted to break the circuit through said conductors at a predetermined temperature.

JERRY C. WIESNER. JAMES R. CAREY.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 905,597 Smyser Dec. 1, 1908 1,369,475 Schneider Feb. 22, 1921 1,504,944 Cook Aug. 12, 1924 1,629,844 Soto May 24, 1927 2,319,477 Rush May 18, 1943 

